/*
* Copyright (C) 2022 Huawei Device Co., Ltd.
* Licensed under the BSD License, (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
*     https://opensource.org/licenses/BSD-3-Clause
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/

import {Description} from '../Description';
import {Matcher} from '../Matcher';
import {BaseMatcher} from '../BaseMatcher';

/**
 * Is the value a number actually not a number (NaN)?
 */
export class IsNaN extends BaseMatcher<Number> {
  private constructor() {
    super();
  }

  public matches(item: number): boolean {
    return Number.isNaN(item);
  }

  public describeMismatch(item: number, mismatchDescription: Description): void {
    mismatchDescription.appendText("was ").appendValue(item);
  }

  public describeTo(description: Description): void{
    description.appendText("a double value of NaN");
  }

  /**
     * Creates a matcher of {@link Double}s that matches when an examined double is not a number.
     * For example:
     * <pre>assertThat(Double.NaN, is(notANumber()))</pre>
     *
     * @return The matcher.
     */
  public static notANumber(): Matcher<Number> {
    return new IsNaN();
  }
}
